Cop

n.
  1. The top of a thing; the head; a crest.
  2. A conical or conical-ended mass of coiled thread, yarn, or roving, wound upon a spindle, etc.
  3. A tube or quill upon which silk is wound.
  4. (Mil. Arch.) Same as Merlon.
  5. A policeman.
    6. Cop waste ,
    a kind of cotton waste, composed chiefly of remnants of cops from which the greater part of the yarn has been unwound.